Apparatus for drilling boreholes with explosive charges



Dec. 26, 1961 H. ROBINSON, JR., ETAL 3,014,423

APPARATUS FOR DRILLING BOREHOLES WITH EXPLOSIVE CHARGES Filed Nov. 27, 1959 2 Sheets-Sheet 1 FIG. 2.

INVENTORS. LEON H ROBINSON JR., ROBERT H. FRIEDMAN,

ATTORNEY.

Dec. 26, 1961 H. RoB1NsoN,JR.. ETAL 3,014,423

APPARATUS FOR DRILLING BOREHOLES WITH EXPLOSIVE CHARGES Filed Nov. 27, 1959 2 Sheets-Sheet 2 FIG. 5.

INVENToRs, LEON H.RoB1NsoN JR., BYROBERT H.FR|EDMAN,

FIG.

A* ATTORNEY.

United States Patent (Milice 3,014,423 Patented Dec. 26, 1961 3,014,423 APPARATUS FOR DRILLING BOREHOLES WITH EXPLOSIVE CHARGES Leon Haynsworth Robinson, Jr., and Robert H. Friedman, Houston, Tex., assignors, by mesne assignments,

to Jersey Production Research Company, Tulsa, Okla.,

a corporation of Delaware Filed Nov. 27, 1959, Ser. No. 855,681 4 Claims. (Cl. 102-20) This invention relates to the drilling of boreholes, and more particularly to drilling boreholes utilizing a succession of explosive charges including shaped jet charges.

In connection with drilling boreholes for the purpose of exploiting possible hydrocarbon deposits in the earth, it has been known to utilize explosive charges for the purpose of expediting drilling operations. It has also been known to use shaped jet charges in combination with nondirectional blasting charges. Examples of the prior art use of explosive charges for drilling operations may be found in U.S. Patent No. 2,897,756 to L. Borins et al. and U.S. Patent No. 2,587,243 to W. Sweetman.

Previous attempts to use explosive charges for earth drilling have been characterized by very slow penetration rates, great expense, and the necessity for using more or less cumbersome equipment. While the development of shaped jet charges has made the use of explosives for drilling more attractive 4because. of the directional characteristics of the shaped charge, it has not proved to be a cure-all for the deficiencies of explosive drilling. A prime reason is that, while the shaped charge is capable of penetrating further into the earth than can a nondirectional explosive charge, it blasts a hole that is quite wide at its mouth but which narrows rapidly and terminates in an elongated cavity that is far too narrow to accommodate a well or drill pipe. The use of blasting charges in the manner taught by the aforecited Borins et al. patent has not particularly helped the situation because the blasting charges do not deepen or widen the hole drilled by the shaped charge to any great extent.

The present invention makes use of a well pipe having a landing seat or nipple at or near its lower end. The well pipe is connected to conventional mud circulating equipment at the surface so that drilling fluid is pumped down the well pipe and up the annulus around the well pipe. Use is made of elongated shaped jet charges and elongated nondrectional gauging charges adapted to be pumped down the well pipe, and further adapted to seat on the landing nipple or seat so that a differential pressure is built up thereacross.

The jet charges and gauging charges are injected into the stream of drilling iluid going down the well pipe, according to a predetermined sequence. First, a shaped charge is pumped down the well pipe. After it seats on the landing seat, the explosive portion of the jet charge is spaced from the bottom of the borehole a predetermined distance of predetermined magnitude that is built up across the shaped charge. Responsive to differential pressure, the charge is detonated so as to blast a hole in the earth at the bottom of the well bore. A gauging charge is then landed on the seat so as to extend into the hole produced by the preceding shaped jet charge. Preferably, the gauging charge is long enough to penetrate substantially the entire length of the hole blasted by the shaped charge. The gauging charge, which may be of a brisant or unbrisant explosive material or a combination thereof, is detonated while tamped 'with drilling uid and preferably while under a hydrostatic pressure of at least 1000 p.s.i. Drilling iluid is circulated after each detonation of a shaped charge and a gauging charge so as to remove earth fragments and fragments of the explosive charge housing. Preferably, the explosive charges are injected into the drilling stream so as to be spaced apart substantially to 4000 feet, and the drilling fluid is circulated so that particles therein are travelling at the rate of between 100 and 400 feet per minute so that the successive explosive charges are detonated between 1 and 10 minutes apart.

The invention will be more completely understood, and the various objects and features of the invention will become apparent upon consideration of the following description thereof when taken in connection with the accompanying drawings, wherein:

FIG. l is a perspective diagram of a portion of equipment that may be used at the earths surface in connection with the practice of the invention;

FIG. 2 is a view of a shaped jet charge being pumped down a well pipe, showing a preferred construction of the lower end of the well pipe;

FIG. 3 is an elevational view, partially in section, of the explosive charge magazine housing shown in FIG. \1, which view shows certain of the details of the magazine housing;

FIG. 4 is a fragmentary cross-sectional view taken along section 4 4 of FIG. 3;

FIG. 5 is a top view of the magazine housing shown in FIG. 4;

FIG. 6 is a cross-sectional view taken along section 6 6 of FIG. 3;

FIG. 6A is a fragmentary top view of the explosive charge container shown in FIG. 3.

In FIG. l there is shown surface equipment for use in connection with the present invention. The usual drilling rig 1 is provided with an explosive charge loaders platform 3 at a distance above the drilling floor 20 determined by the length of well or drill pipe to be run into the hole to be drilled with the apparatus. An explosive charge housing 5 for storing explosive charges is located on the loaders platform 3.

The usual traveling block 9 is suspended from a crown block (not shown) by cables in the usual manner. Located between the swivel 19 and hook 10 is an explosve charge magazine housing 17 which is illustrated in detail in FIGS. 3 through 6 and 6A. Connected to swivel 19 is a kelly joint 18 which extends through the rotary table 21 into the surface casing 25. The function of the magazine housing is to provide a remotely controlled apparatus for injecting a plurality of explosive charges into the well according to a predetermined sequence. Drilling fluid is circulated through the magazine housing 17 into the swivel 19 and kelly joint 18 from the usual standpipe 15 and hose connection 13. A mud pump (not shown) supplies pressurized drilling fluid to the standpipe. Below the drilling oor 20 is located the usual mud return line 27 which may be controlled by a valve 29. The mud control line is hydraulically coupled to the annular space around the drill pipe in the usual manner.

As shown most perspicuously in FIG. 2, the drill or well pipe 28 is provided with a landing seat 31 at or near its lower end. The purpose of this landing seat is to receive a collar 45 tted around an explosive charge 33 which is pumped down the well. When the collar 45 lands on the seat 31, tlow of drilling fluid down through and out the lower end of the well pipe will be either stopped or substantially reduced so that a differential pressure will be built up across the explosive charge. As will be `described in detail below, dilerential pressure is used for the purpose of firing the explosive charge.

The details of the explosive charge magazine housing 17 are shown in FIGS. 3, 4, 5, 6, and 6A. The housing 17 is suspended from the traveling block by the usual hook 10 and bales 11. A housing bonnet 127 is connected to the lower part 129 of the magazine housing by a plurality of bolts connecting together the housing 3 anges 131, 132. A drilling uid inlet port 122 and an exhaust port 152 are provided in the housing 17. A coupling pipe 123 interconnects the inlet port to the drilling fluid hose 13. The exhaust port 152 is connected to swivel 19 by suitable pipes and a valve 155. The housing is also provided with an additional port 134A in housing bonnet 127 for the purpose of loading the magazine with charges. A suitable plug 132 is provided for the purpose of sealing port 134A after the magazine has been loaded with explosive charges, so that drilling fluid cannot escape from the housing through port 134A.

Enclosed within magazine housing 17 is an explosive charge transport member 147 comprising an upper end section 134, a lower end section 136, and a plurality of tubes which are designated by Roman numerals I through XI for the purpose of acting as open-ended explosive charge receptacles. The transport member is supported between shafts 105 and 139 which respectively extend through the bonnet 127 and the lower portion 129 of the magazine housing. Shafts 105 and 139, respectively, include bearing flanges 101 and 140, which respectively are fitted between bearing members 108 and 144. The bearing members 108 and 144 are respectively positioned in the ends of the housing bonnet 127 and lower housing member 129. Retaining nuts 107 and 142 are provided for the purpose of holding the shafts 105 and 139 in place.

A ratchet gear or wheel 101A is afxed to the upper end of shaft 105. As shown most perspicuously in FIG. 5, a solenoid-acuated pawl 111 is positioned on the housing bonnet 127 by guide member 113 to engage the notches in the ratchet wheel 101. The notches are provided with small recesses at the bottoms thereof so as to minimize back-lash when the pawl engages the ratchet wheel. The pawl may be biased by a spring means in the conventional manner to normally fit into the notches of the ratchet wheel. The solenoid 110 is provided for the purpose of momentarily disengaging the pawl from the notches. The solenoid may be energized through a control cable 121 which extends to the drillers position on the derrick floor. A small hole 110B is provided in the housing bonnet 127 and an eye 110C is provided in the pawl 111 so that the pawl may be locked out of engagement wih the notches of the ratchet wheel by means of pin 110A. An auxiliary pawl 115, which may be spring-biased into engagement with the ratchet wheel and which may pivot around a pivot point 119, is provided for the purpose of engaging the ratchet wheel and to permit counterclockwise movement of the ratchet wheel when the shaft 105 is manual turned in a counterclockwise direction. Pin 119A is adapted to fit through eye 119C ino hole 119B to lock the pawl 115 out of engagement with the ratchet wheel. Pawl 115 is normally spring-biased into engagement with the ratchet wheel by means of a spring (not shown) which tends to rotate it in a counterclockwise direction as viewed in FIG. 5.

Inasmuch as the explosive charge capsules contemplated for use in connection with the present invention are considerably less dense than the drilling mud that is ordinarily used, the charges will tend to float in the drilling mud. For the purpose of holding the explosive charges wihin the receptacles in the transport member, there is provided at the top of each receptacle of flipper member 137. The flipper is normally held in a horizontal position by a spring means (not shown) and is rotated to a vertical direction when an explosive charge is slid into the receptacle corresponding thereto. As soon as the explosive charge is in the receptacle, the ipper 137 will swing to a horizontal position to prevent the explosive charge from oating up out of the receptacle.

In each of the receptacles there are a number of ports 150 for the purpose of permitting free Huid ow through the interior of the housing. Likewise, ports 148 and 138 are provided for the same purpose in the upper and lower portions of the transport mechanism.

A spiral spring 145 is affixed to a bar or strap 141 and to the lower end of shaft 139. The spring spirals in a manner such that it will be wound when the ratchet wheel 101A is rotated in a counterclockwise direction as viewed in FIG. 5. Thus, the spring will tend to rotate shaft 139 responsive to withdrawal of pawl 111 from a notch of the ratchet wheel after the spring is wound. Strap or bar'141 is bolted to the lower end of the housing 17 The operation of the apparatus described in FIGS. l through 6 is as follows. Before the apparatus described above is used, a borehole may be drilled in the earth through the relatively soft earth formations near the earths surface by means of conventional rotary drilling equipment. Alternatively, the apparatus described above may be utilized from the time that the well is spudded. However, it usually will be found to be more economical to use a rotary drilling procedure for the initial stages of drilling the borehole until relatively hard earth formations are encountered.

When a hole has been drilled to a desired depth in the conventional manner, the rotary drill pipe may be pulled out of the hole and a thinner walled pipe 28 such as shown in FIG. 2 may be substituted therefor. An advantage associated with utilizing thinner walled pipe is that larger explosive charges can be run down the pipe. The lower stand of the pipe may be provided with reamer blades 28a for the purpose of reaming the hole should such become necessary. Likewise, the lowermost edge of the pipe may be studded with diamonds to rotary-drill for short time intervals should relatively soft earth formations be encountered.

Plug 132 ((see FIG. 5) is removed from the magazine housing, pawl 111 is locked out of engagement with ratchet wheel 101, and pawl 115 is allowed to engage the ratchet wheel. Explosive charges are inserted into the magazine housing into each of the explosive charge receptacles. The charge transport means is rotated by a wrench or other means that engages the hex end 103 of shaft 105. When the transport mechanism is fully loaded with explosive charges, with shaped charges, and gauging charges in a predetermined sequence around the mechanism, pawl 111 is released to engage the ratchet wheel and pawl 115 is locked out of engagement with pin 119a. Seal 132 is locked into position and drilling fluid pressure is applied so that drilling fluid is circulated down the well pipe. Initially, a shaped charge 33 is injected into the drilling uid stream. At intervals of approximately 1 to '10 minutes, the driller may inject the other charges in the magazine housing by energizing solenoid through control line 121 from a suitable source of electrical power (not shown). When a shaped charge is seated at the bottom of the well pipe, manifestly the differential pressure .across the shaped charge will detonate the charge as described above. An elongated tapered hole will be produced. Drilling fluid circulation will continue so that detritus including earth fragments, fragments of the shaped charge container, and the fragments 53 and 55 of the firing collar 45 will be circulated up the annulus around the well pipe.

One or more gauging charges are landed in succession at the bottom of the pipe after each shaped charge. It will be found that usually one gauging charge is sucient to enlarge the entire hole to a desired diameter. After a gauging charge is detonated, it will be found that an almost perfect cylindrical hole will be blasted into the earth formations by the gauging charge. The hole will be amazingly uniform in diameter and will be of a suflciently large diameter so that the well pipe 28 may be lowered to the depth of the hole blasted by the shaped charge 33. It will be found that, by virtue of the fact that the gauging charge is tamped and under hydrostatic pressure, the volume of earth that is spalled by the gauging charge will be between 50 and 100 percent greater than when the explosive charge is not tamped and is not under hydrostatic pressure. A hydrostatic pressure of at least 1000 pounds has been found to be satisfactory. Much higher hydrostatic pressures may be utilized with the effectiveness of the gauging charge increasing as the hydrostatic pressure is increased. Detritus produced by the gauging charge may be circulated out of the hole formed as described above, as the well pipe is lowered.

If the well pipe used as described above is of the type referred to as casing, cement may be circulated when the borehole has reached desired depth for the purpose of bonding the pipe to earth formations surrounding the borehole. The usual completion techniques may then be followed and the well produced. In this manner a costly round-trip is avoided.

The invention is not to be restricted to the specific structural details, arrangement of parts, or circuit connections herein set forth, as various modifications thereof may be effected without departing from the spirit and scope of this invention.

What is claimed is:

1. Apparatus for injecting elongated explosive charge containers into a well pipe during borehole drilling operations involving circulation of drilling fuid down through the well pipe and up the annulus around the well pipe, comprising: a housing; a drilling iiuid inlet port at one end of said housing adapted to be coupled to a source of pressurized drilling fluid; a drilling fluid exhaust port opposite said inlet port at the other end of said housing, adapted to the hydraulically coupled to the well pipe; a rotatable explosive charge transport member within said housing having a plurality of open-ended explosive charge receptacles disposed in a circular ring about the axis of rotation of said transport member and positioned in said housing so that the charges will be aligned between said exhaust port and said inlet port in succession as the transport member is rotated so that said charges will successively pass through said exhaust port under impetus of uid pressure from said inlet port; first and second shafts connected to said transport member at opposite ends thereof, extending through opposite ends of said housing; bearing flanges connected to said shafts; bearing means in said housing at opposite ends of said housing for supporting said bearing anges; a spiral spring connected to said first shaft and to said housing, adapted when wound, to rotate said transport member; a notched ratchet wheel connected to said second shaft; a pawl positioned to engage the notches of said ratchet wheel; an electromagnetically energized actuating means connected to said pawl adapted to momentarily disengage said pawl from the ratchet wheel to allow said transport member to rotate through a predetermined angle under the impetus of said spiral spring; a loading port positioned in said housing so that explosive charges inserted therethrough will enter said charge receptacles; and a plurality of spring-actuated flippers at the top of each charge receptacle adapted to permit entry of said charges into said receptacles and to prevent the charges from floating out of said receptacles when said housing is filled with drilling iiuid.

2. Apparatus for injecting elongated explosive charge containers into a well pipe during borehole drilling operations involving circulation of `drilling fluid down through the well pipe and up the annulus around the well pipe, comprising: a housing; a drilling fiuid inlet port at one end of said housing adapted to be coupled to a source of pressurized drilling iiuid; a drilling uid exhaust port opposite said inlet port at the other end of said housing, adapted to be hydraulically coupled to the well pipe; a rotatable explosive charge transport member within said housing having a plurality of open-ended explosive charge receptacles disposed in a circular ring about Ilthe axis of rotation of said transport member and positioned in said housing so that the charges will be aligned between said exhaust port and said inlet port in succession as the transport member is rotated so that said charges will successively pass through said exhaust port under impetus of fiuid pressure from said inlet port; first and second shafts connected to said transport member at opposite ends thereof, extending through opposite ends of said housing; bearing flanges connected to said shafts; bearing means in said housing at opposite ends of said housing for supporting said bearing anges; a spiral spring connected to said first shaft and to said housing, adapted when wound, to rotate said transport member; a notched ratchet wheel connected to said second shaft; a pawl positioned to engage the notches of said ratchet wheel; an electromagnetically energized actuating means connected to said pawl adapted to momentarily disengage said pawl from the ratchet wheel to allow said transport member to rotate through a predetermined angle under the impetus of said spiral spring; a loading port positioned in said housing so that explosive charges inserted therethrough will enter said charge receptacles; and means operatively associated with said charge receptacles adapted to permit entry of said charges into the receptacles and to prevent the charges from floating out of the receptacles when said housing is filled with drilling uid.

3. Apparatus for injecting elongated explosive charge containers into a well pipe during borehole drilling operations involving circulation of drilling fluid down through the Well pipe and up the annulus around the well pipe, comprising: a housing; a drilling fluid inlet port at one end of said housing adapted to be coupled to a source of pressurized drilling fluid; a drilling fluid exhaust port opposite said inlet port at the other end of the housing adapted to be hydraulically coupled to the well pipe; a rotatable explosive charge transport member within said housing having a plurality of open-ended explosive charge receptacles disposed in a circular ring about the axis of rotation of said transport member and positioned in said housing so that the charges will be aligned between said exhaust port and said inlet port in succession as the transport member is rotated so that said charges will successively pass through said exhaust port into the well pipe under impetus of fluid pressure from said inlet port; first and second shafts connected to said transport member at opposite ends thereof, extending through opposite ends of said housing; bearing flanges connected to said shafts; bearing means in said housing at opposite ends of the housing for supporting said bearing iianges; a spiral spring connected to said first shaft and to said housing, adapted when wound, to rotate said transport member; means connected to said transport member and operatively positioned with respect to said charge receptacles adapted to permit entry of charges into the receptacles and to prevent charges from floating out of the receptacles when said housing is filled with drilling fiuid; and control means operatively connected to said transport member adapted to selectively rotate said transport member under the impetus of said spiral spring so that said transport member rotates through a predetermined angle when actuated to permit entry of said explosive charges in succession into the well pipe; and electrically actuable means connected to said control means for actuating said control means.

4. Apparatus for injecting elongated explosive charge containers into a well pipe during borehole drilling operations involving circulation of drilling fluid down through the well pipe and up the annulus around the well pipe, comprising: a cylindrical housing; a drilling uid inlet port at one end of said housing adapted to be coupled to a source of pressurized drilling fluid; a drilling iiuid exhaust port opposite said inlet port at the other end of the housing adapted to be hydraulically coupled to the well pipe; a rotatable explosive charge transport member within said housing having a plurality of open-ended explosive charge receptacles disposed in a circular ring about the axis of rotation of said transport member and positioned in said housing so that the charges will be aligned between said exhaust port and 7 said inlet port in succession as the transport member is rotataed so that said charges will successively pass through said exhaust port into the well pipe under impetus of uid pressure from said inlet port; shaft means connecting said transport member to said housing for rotative support within said housing; means connected to said transport member and operatively positioned with respect to said charge receptacles adapted to permit entry of charges into the receptacles and to prevent charges from floating out of the receptacles when said housing is lled with drilling fluid; and means associated with said explosive charge transport member adapted to re- References Cited in the le of this patent UNITED STATES PATENTS 1,955,166 Bannister Apr. 17, 1934 2,048,451 Johnston July 21, 1936 2,250,574 Dodge July 29, 1941 2,615,369 Jansson et al. Oct. 28, 1952 

